Assassination Den-O
by Kamen Rider Super-Fan
Summary: After entering another world within the timestream, the Denliner crew found themselves in a world where almost all of the moon is gone and a certain yellow octopus/teacher caused it. Now they teamed up with a young man from that world to stop Koro-Sensei from blowing up Earth next March by training him to fight the Imagins in that world and to become an assassin while they fight ag
1. Chapter 1

**Hey, here's what you have all been waiting for… my new Den-O story! Oh and you'll notice some changes to my character that you've seen in the preview though.  
**

 **I do not own Assassination Classroom or Kamen Rider Den-O  
**

 **Timeline 1: A New World Time.**

* * *

In a big wasteland, where there is sand everywhere, big canyons and the sky is strangely rainbow colored. An electric keyboard kind of tune played and a futuristic white and red bullet train appeared and three different colored carts was attached to it. This is the train of time, DenLiner.

Inside the train, the train was four beings and two people.

The first monster was red from head to toe with red body armor that had black markings on it. On his waist was a belt with a metal peach on it. His shoulder pads had spikes on them and his face looked like that of an oni with silver teeth, black eyes, and long red horns on his head. His name is Momotaros.

The second was donned mostly in bright blue armor that looked more like carapace in some spots. On each of his shoulders was a single hexagonal gray plate. His face seemed close to what someone would expect to see on a turtle. His eyes were a bright orange which caught attention whenever someone would glance at his face. His name is Urataros.

The third had a bulky body and was wearing a jacket with furry lining. His head was covered halfway with a helmet of some kind that had a horn sticking out of the forehead and a visor acted as a pair of eyes. He also pair of legs that looked just as muscular with boots. He was colored mostly gold with the helmet being black. His name is Kintaros

Finally there was the last monster. He looked like he had a large purple trench coat on which had black designs on it. He was wearing white gloves, purple pants, and purple boots. The shoulders had fins running from them as well. His head was purple and very dragon-like. He had both fins and whiskers running along the sides with a pair of horns on top of his head. A long braid of purple hair ran from the back of his head while it looked almost like he had a pair of headphones. His name is Ryutaros.

The fifth person is an elderly man wearing a suit, he has a cane and he's currently eating fried rice with a flag on it. This is the Owner of DenLiner.

The last person was was a young woman who was dressed in a tight waitress outfit consisting of black tight pants with white stripes, red heeled boots, a pair of red gloves and black sleeves that covered her arms, a white halter top that had no shoulders but still had a collar, a white cap on her head keeping her hair black hair with a pink streak combed back, and her arms were covered in a multitude of watches. Her name is Naomi.

In the past, Momotaros, Urataros, Kintaros, Ryutaros met an unlucky young man named Ryotaro Nogami and teamed up with him to protect the timestream from their own kind, Imagin, as a protector of time called Den-O. During their journey to fight against them, they met enemies, allies such as Zeronos and New Den-O, Ryotaro's future grandson and saved many people. Now Ryotaro retired and they had to count on his grandson to protect the timestream. They're still willing to help out at times, despite the fact that they constantly argue with each other despite being allies.

Speaking of which, what they're doing now it…

"Hey, you little brat! Come back here with MY pudding!" Momotaros yelled, chasing Ryutaros who laughed while holding up his favorite pudding.

"Moron, moron, moron, moron, moron...!" Ryutaros playfully said, avoiding the Red Imagin with ease thanks to remarkable flexibility and dance talent.

"They are as noisy as usual." Urataros commented while reading a book.

Kintaros is sleeping as usual.

Owner was simply eating his fried rice as always and ends with the flag falling down.

As this was going, the Denliner had suddenly shook causing them to stop what they were doing.

"What was that?" questioned Urataros, closing his book.

"Ah, it's probably nothing." Momotaros shrugged.

The train then shook again.

"This isn't good." said Urataros.

"Indeed it isn't." Owner said, slowly getting up from his seat and twirled his cane around. "Shall we check the Denbird to see the status outside?"

"Yeah, let's go!" Momotaros said as they ran to the Denbird. Ryutaros and Naomi were trying to wake Kintaros to let him know the situation.

Momotaros and Urataros got into the cart where the DenBird is at, which is a white and blue Honda XR250, and they see a black and purple portal.

"What the heck is that!?" Momotaros exclaimed.

"Who knows. But let's stop this train just in case." Urataros suggested.

"No need to tell me twice!" Momotaros got onto the bike and pressed the brake. DenLiner slowed down for a moment… only about to be dragged in. "What!?"

"Sempai!" Urataros went in front of DenBird and tried to help Momotaros with the brakes.

 **(Dinning Cart)  
**  
"Oi Kuma-chan, wake up!" Ryutaros said while shaking him.

Naomi placed a finger on her chin before getting an idea.

"Cry!" Naomi said, making Kintaros wake up.

"Cry!?" Kintaros got up and cracked his neck. "I'll make you cry!"

"Mou… Baka!" Ryutaros smacked Kintaros' head with a paper fan.

 **(DenBird)**

"C'mon! Push harder!" Momotaros yelled as he and Uarataros were pushing on the brakes.

"I'm trying!" Urataros said.

Sadly for them, they couldn't stop the train on time and DenLiner got sucked into the portal before disappearing, thus making them no longer around.

* * *

 **(In another world)**

Momotaros was on the ground, unconscious in a forest. Well instead of unconscious…

"Naomi… more coffee…" Momotaros said in his sleep.

"Sempai, wake up!" Urataros' voice called out.

"Shut up, you perverted turtle...!" Momotaros groaned in his sleep.

"Poke, poke, poke, poke, poke..." laughed Ryutaros as he was poking at the Red Imagine's face.

"Oi, cut it out already!" Momotaros yelled, slapping the purple Imagine's hand away. It took him a moment to realize that all of them were in some forest. "Huh? Where are we!?"

"I don't know, but look up there." said Urataros, pointing up at the sky, more specifically the moon.

"Wh-Wh-What the hell is this!?" exclaimed Momotaros.

"Ah, the moon!" cried Ryutaros.

"Hmm...?" questioned Kintaros. "Oh the moon is broken." he nodded before realizing what they had just seen and what he said earlier. "What!? The moon...?"

"It's broken! Broken Broken Broken Broken Broken Broken!" Ryutaros yelled childishly.

"WHAT THE HELL IS GOING ON!?" Momotaros yelled.

"Guys… I have a feeling that we're not in our world now." Urataros said, catching their attention before…

"EHHHHH!?" Momotaros yelled.

* * *

 **(Somewhere else)  
**  
At a rural area; a young man was laying down on a grassy slope. He had black hair that covered his ears, he also wore a school uniform, which is a gray coat with a black shirt, gray pants and black shoes. He opened up his eyes, which revealed that his left eye was the same color as a ruby and his right eye was the same color as a blue sapphire. His name is Neku.

Neku yawned a bit while stretching his arms.

"That was some nap." Neku yawned as he scratched the back of his head. Neku heard something and looked to his left to see someone that caught his attention.

The someone is a young petite framed boy with light blue hair and azure eyes, he could easily be mistaken as a girl if you don't know him. He was wearing a blue vest with a black tie, white shirt and blue pants with black shoes.

"Nagisa…" Neku recognized. He was about to call out to him before he noticed three other guys.

The first one has short, spiky, black hair which is dyed blonde around the sides. He has a bulky body which he uses to intimidate people with and green eyes. His name is Ryoma Terasaka

The second one has black hair, tan skin and black eyes. His name is Taisei Yoshida.

The third guy has dyed blonde hair and black eyes, he's also wearing the school uniform. His name is Takuya Muramatsu.

' _What're those guys doing with Nagisa?'_ Neku thought before crouching down to the ground, deciding to watch before taking action.

"That octopus' face changes color with his moods, right? You're hanging around with that guy who said he'd be observing, aren't you?" Terasaka asked.

"So they're talking about him huh?" Neku whispered his thought.

Nagisa took out a notepad.

"Sort of. I remember that green stripes appear when he's calm." Nagisa started. "If a student gives an incorrect answer, his face becomes dark purple. For a correct answer, it becomes bright red."

' _Yeah. I remember when I made a correct answer, his face turned red and that was only a guess.'_ Neku thought.

What's interesting is how after lunchtime…" Nagisa started.

"I don't need to know." Terasaka interrupted him before walking towards the blue haired boy and taking out a green combat knife. "I've got a plan. It's for when he's got his most [careless] face on, you'll stab him."

' _What's he getting at?'_ Neku thought, not liking it.

"Me? B-But…" Nagisa stuttered.

"Don't pretend to be some goody-goody. We're Class E ain't we?" Terasaka reminded.

Terasaka isn't wrong, the school they go to, Kunugigaoka Junior High, is a prestigious private school located in Tokyo, Japan. It is renowned for being one of the top schools in all of Tokyo and has a high rate of successful students. The school itself is actually an academy as it also has a high school that the students of Classes A to D enroll to through an escalator system and students from other schools enter through a transfer student exam. However, Class E is a class of those who couldn't keep up with this school's education level, which earned the nickname [E as in End Class]. The classroom is a rundown school building up in a mountain and there, the students are treated no different than garbage.

Neku got out of his thoughts before looking at Terasaka, who was holding a small bag in front of Nagisa's face.

"No matter…" Terasaka grinned like a madman. "What methods we use to reach that goal." he gave it to Nagisa. "Don't screw up now, Nagisa-kun~."

Muramatsu laughed as the three left towards the building.

Neku sighed before he got up and went towards Nagisa.

"Nagisa!" Neku called out.

The blue haired boy noticed him.

"Neku…" Nagisa recognized before the different eyed boy stopped in front of him.

"Hey…" Neku said before catching his breath from the running. "I saw what you and Terasaka were talking about."

Nagisa looked down a bit before looking at his friend.

"Yeah, he wanted to know what I knew so far about our new teacher. But to be honest, I never expected that it would involve me in a plan." Nagisa said.

"Yeah, knowing those guys it would probably hurt you." Neku said as he scratched the back of his head while recalling about what Terasaka did in the second year at this school and on this mountain too.

Before the two can talk more…

 ***BOOM!***

Something landed onto the ground, kicking up a little bit of a dirt cloud and making a sound wave.

"Hello there, I'm back." Neku and Nagisa looked to see someone, or something with a male voice.

He has the appearance of an octopus. He is about three meters tall, and has a large, bulbous head with a large smile, beady eyes. He has two feelers as arms, with two fingers each. He wears a black academic dress, a small black square academic cap with a yellow tassel, and a black tie with a yellow crescent-shaped moon on it. Oh and he's carrying a missile for some reason.

"Okay, hi sir." Nagisa greeted a neutral tone.

"Welcome back." Neku greeted. "What's with the missile?"

"Oh, it's a souvenir." the octopus said. "The JSDF ambushed me in the sea of Japan."

Neku and Nagisa sweatdropped a bit. How did these guys get someone like him? Well there was a time, not that long ago, when the moon wasn't crescent shaped.

* * *

 **(Flashback)**

 _Neku couldn't believe what he was seeing right now. Heck, the entire class was surprised to see something that's very unnatural in here. After all, it's very unnatural to see a yellow octopus dressed like a teacher with three guys, more like two guys and one girl, in suits._

 _"Hello~! How are you?" the yellow octopus greeted. "So… I'm the one who blew up the moon."_

 _"Eh?" the E-Class students let out._

 _"Next year I intend to do the same to planet earth. But nevermind that now, I'm gonna be your new teacher. Isn't that exciting?" the yellow octopus asked._

 _'There are so many things wrong with this picture.' the E-Class students thought._

 _'And how is that octopus guy a teacher?' Neku thought that last part._

 _A grown man with spiky hair spoke up._

 _"I'm Karasuma, from the Ministry of Defense." the man named Karasuma introduced. "First of all, I would like you guys to understand that what I'm about to say is classified government information."_

 _Karasuma sighed._

 _"Ah hell, I'll just come out with it." he said, deciding to get straight to the point. "I need you to kill this thing." he gestured to the yellow octopus._

 _'Kill an octopus that's literally standing in front of us?' Neku thought as he and the class gawked at him._

 _"...Er, what? So that guy is an alien who came to attack us?" Takuya Muramatsu asked._

 _"How rude! I was born and raised on earth you know!" the octopus exclaimed while his face turned red._

 _'Just how is an octopus who moves on land born and raised!?' Neku thought._

 _"I'm afraid I can't speak about the particulars, but what he told you is true. This creature who damaged the moon, will also destroy earth next march." Karasuma started. "The world's leaders are the only people who know about this. Before the world is plunged into panic, they are exerting considerable effort to kill him behind the scenes. In other words…" he opened the case in front of him and opened it up then took out a green combat knife. "An assassination." he swung the knife but to the students surprise, the octopus started to move at a REALLY fast pace._

 _'What the heck?' Neku thought._

 _"But at any rate, this guy is fast!" Karasuma started as he swung his knife but the yellow octopus moved as fast as it's going. "Far from killing him, I'm having my eyebrows trimmed by him! Meticulously, even!" Karasuma finished and creature really did trimmed his eyebrows. "He is a super creature possessing enough power to transform a full moon into a crescent. His maximum speed is actually Mach 20! In other words, if this guy were to seriously run away; we would be helpless until the day of our destruction."_

 _'What!?' Neku thought in surprise and shock._

 _"Well, that wouldn't be fun at all. Which is why I made a proposal to the nations of the world." the yellow octopus said as he placed the trimmers away. "I don't want to be killed but…" he placed a hand on Karasuma's shoulder, which made the latter obtain a tick mark "If I become the homeroom teacher for Kunigaoka Junior High School, Class 3-E, then you're welcome to try."_

 _'WHY!?' the E Class students exclaimed in thought._

 _'He's practically begging us to kill him…' Neku thought. 'But knowing some of these guys, they might want some sort of…"_

" _The reward for a successful completion is ¥10,000,000,000!" Karasuma interrupted his thought._

' _Yen!?' the entire class thought, surprised._

' _I stand corrected…' Neku thought, also surprised._

" _It's an appropriate sum. After all the assassination's success means the Earth's salvation." Karasuma said before looking at the octopus teacher, who somehow obtained green stripes. "Fortunately, this guy is looking down on you. See, when the green stripes appear, it's his mocking face."_

' _What is he, a chameleon?'_ _Neku thought._

" _It's only natural. There's no way all of you will be able to kill me when the government couldn't. When they attacked me with a state-of-the-art fighter plane; I gave it a mid-air waxing instead." the octopus said._

' _What's with the cleaning fetish?'_

" _I would like you to strike if the opportunity presents itself. We will provide you with the bullets and knives which are effective to him but harmless to you." Karasuma explained as two subbortanants of his came in with the bullets and knives. "This must be kept a secret from your friends and family. Time is short, if the earth disappears there will be nowhere to run!"_

 _Neku, Nagisa and a green haired girl named Kayano had a look on their faces that looked uneasy. Especially to Neku, he doesn't even like killing at all because he's a pacifist. So for him it's gonna be pretty difficult even if the octopus can move at Mach 20._

" _That's the long and short of it." the octopus clapped his tentacles. "Now everyone, let's spend this final year in a meaningful fashion!"_

' _I'll try but…' Neku looked down. 'There's no meaning when it involves killing, even if the world is at stake here.'_

 _The octopus noticed Neku with that face, now thinking that he'll need to help the different colored eyed teen later on if necessary._

* * *

 _ **(End flashback)**_

"Must be tough, being a target and all." Neku said as the teacher placed the missile next to a tree.

"Nah, not really. The fact that I'm targetted by everyone is proof that I'm powerful after all." the octopus said.

"Yeah. Like I've heard that before." Neku said before the school bell rang.

"Well, 5th period classes are starting." the octopus teacher said as he was walking, with his tentacles, towards the old school building.

"Yes sir." Neku said before he noticed Nagisa with a down expression.

( **With the Taros** )

* * *

"Man, why the hell is the moon destroyed anyway?" Momotaros said as he and the Taros were walking downhill on a mountain towards town.

"Well that's what we're gonna find out." Urataros said.

"You think an Imagin is behind that?" Ryutaros asked as he did a few flips.

"Could be… however, a creature that can break the moon is gonna be our toughest challenge yet." Kintaros cracked his neck.

' _What was your first clue?'_ the three Taros thought.

They soon made it down the mountain, but instead of there being a town; there's a school, a BIG school.

"Wonder who goes to this school?" Momotaros said.

"Oh that's Kunugigaoka Junior High." Urataros said.

"How did you know that?" Kintaros asked.

"There's a sign over there." Urataros pointed at the sign over there.

"How did I not notice that?" Momotaros scratched his head.

"Because you're a Baka." Ryutaros mocked.

"Can it brat!"

"No way, Baka-Momo!" Ryutaros continued to mock before Kintaros covered both their mouths, Urataros noticed a male student on his phone before the blue Imagin possessed him. The student became calm his hair turned straight with a blue streak, his eyes turned blue while he obtained glasses.

U-Student then walked towards the Taros.

"The hell are you doing Kameko?" Momotaros asked.

"Oh, I'm just gonna obtain information on the broken moon and anything that could possible be related to it." U-Student said before he started browsing for info.

"That's actually a good idea." Momotaros placed his right fist into his palm while Kintaros fell asleep on Ryutaros.

* * *

Neku and his classmates were staring at the octopus teacher in slight fear. Earlier, Nagisa walked towards the octopus making him think that an assignment for a poem, which is suppose to end with 'was tentacles all along', and the blue haired boy made a failed attempt to stab the teacher before he hugged the creature and Terasaka pushed a button on a device before Nagisa exploded, literally. He actually filled a toy grenade with gunpowder and some Anti-Sensei BBs

The entire besides Terasaka and his group class got worried.

But they found out that Nagisa was unharmed due to what they thought was a corpse but it was revealed that the teacher was still alive and kicking, it turns out that what protected Nagisa was his skin which he sheds once a month. His face turned black before going out of the classroom and coming back with nameplates of each of the students on where they live. That made both Neku and Nagisa realize that the only way out of this situation was to kill him… even if the former didn't like it.

"Y-You're a real pain in the ass! COMING HERE ALL OF A SUDDEN WITH YOUR 'I'M GONNA BLOW UP THE EARTH' AND 'ASSASSINATE ME' AND ALL THAT…" Terasaka, who was on the ground, accused. "WHAT'S WRONG WITH USING AN IRRITATING KILLING METHOD ON AN IRRITATING GUY!?"

The octopus' head turned bright red with a circle.

"Irritating? Nonsense, your idea was excellent." the octopus teacher reached his tentacle out to Nagisa and patted him on the head. "Especially Nagisa. You get a perfect score for keeping the movement of your body entirely natural until the moment you closed in. You attacked me at a magnificent opportunity."

Nagisa was surprised while Neku was glad that their new teacher wasn't mad now.

"However, excluding Mr. Neku." the octopus teacher's head turned purple with an X. "Terasaka and the others held no regard for Nagisa's welfare. Students like that do not have the right to kill me."

"Excluding me?" Neku asked.

"Of course, after all you tried to stop Nagisa a few seconds before the grenade blew up." the teacher said to him.

"Well somebody's gotta be a good friend for this guy from blowing himself up." Neku said.

"Somehow I don't want to hear that from a guy that always get bad luck." Nagisa said.

"Name one time."

"This morning you stepped on a can and then fell on your head." Nagisa said.

"Name three times." Neku said.

"You fell down a manhole, got stuck up on a tree with a bicycle and yesterday bird poop fell on your shoulder." Nagisa counted.

"Okay, I'm very unlucky." Neku said with a comical depressing aura.

"As I was saying…" the octopus teacher said, getting everyone's attention. "Let's have an assassination that will make people smile and puff out their chests with pride. Each and everyone of you can do that. You are talented assassins with hidden strength. That is advice from your teacher, as a target."

Neku sat back down at his seat.

' _I don't actually like to fight or killing, but I guess it wouldn't hurt to try.'_ Neku thought as the octopus teacher took out a burning mark on the teacher's desk.

"Now then, here's a problem for you Nagisa." the octopus teacher started. "I don't even have the slightest intention of being killed, because after enjoying my time with all of you until March, I'm going to blow up the Earth. If you don't want that, then what will you all do?"

Nagisa thought about it for a moment before smirking.

"Before that happens, we're gonna kill you." Nagisa said.

"Nurufufufu~." the octopus laughed while his head obtained the green stripes. "That's the spirit." he then turned to all the students. "No one leaves until I'm vanquished!" he joked.

' _You're kidding right?'_ Neku thought after the classroom complained about that.

Nagisa went back to his desk and took a quick peek at the teacher, who sat down at the desk at Mach 20 and started cleaning the nameplates.

* * *

 **That proves one thing, we're assassins and our target is our teacher whether we like it or not. Ah well, that's life… even if we gotta take a life which is kinda odd in my opinion. While the class has their assassination weapons out, I overheard Nagisa and Kayano talking about the Japanese word for unkillable, they must be figuring out what name what would be good for the octopus teacher. I was proven right when Nagisa said the perfect name for him.**

 **Koro-Sensei.**

 **Honestly, that feels like the right for him. Just us vs Koro-Sensei for the fate of the world.**

 **Here, in our Assassination Classroom.**

 **-Neku**

* * *

( **With the Taros** )

"What did you learn so far?" Kintaros asked Urataros, who unpossessed the student.

"Well so far I've learned that the destruction of the moon happened a few months ago." Urataros said while he was leaning against a tree. "However, the cause of the moon's destruction is currently unknown."

"So we're at a dead end here!" Momotaros groaned.

"Not exactly, there were also sightings of some yellow creature that looks like an octopus that can fly around town."

"Flying octopus? Kameko, you are not making any sense." Momotaros said.

"That's because you're a moron, Baka-Momo!" Ryutaros playfully said.

"Be quiet brat!" the red Imagin barked.

"No way, Baka-Momo!"

"Anyway!" Urataros said, catching their attention. "We need to find a door back to DenLiner and a way back home."

"I wonder how Owner's doing…" Kintaros said.

* * *

( **With Neku** )

Neku just packed up his school supplies in his bag. He then went out the door and sees Koro-Sensei bidding some students farewell while he was watering some plants.

' _That guy is good with plants despite him being the future destroyer of the world.'_ Neku thought as he walked passed him.

"Neku." Koro-Sensei called out to the different eye colored teen.

"Hm?" Neku stopped before he noticed a silver star necklace in front of his face, being held by his teacher.

"If what Nagisa said was true about you being unlucky a bunch of times, here's this to hopefully improve your luck." Koro-Sensei said.

Neku stared at the necklace before taking it.

"Thanks Koro-Sensei." he placed the necklace in his pocket before running off. "See ya!"

"Have a pleasant evening." Koro-Sensei said before he went back to the flowers.

Neku ran down the mountain while he was placing the necklace around his neck… until he tripped on his shoelace and fell down onto the ground making him roll down the mountain. The rolling eventually led him down to halfway towards the bottom of the mountain and crashed into a tree.

"Ow…" Neku groaned in pain before he slowly got up. "Well at least it improved by a little, usually whenever I trip I hurt my skull. But this time it's my forehead."

Neku laughed slightly before he started to walk away while rubbing his forehead. He soon made it down the mountain and near the main building… until he stepped on a can which made him slip and fell on his back.

"Ow…" Neku groaned, again, and notices the can. He then noticed a couple of students that he never knew in a group and he noticed one of them snickering. 'Of course someone from the other classes would do that on purpose.'

Neku got up before he grabbed the can and saw a trash can. The different eyed teen threw the can at the trash can, but it bounced back and went towards one of the students then it hit him on the back of his neck.

The students, who look like they're from D-Class stared at Neku before the different eyed teen ran away.

"Get him!" the leader of the group said before they ran after him.

( **A few minutes later** )

"Man these guys are persistent!" Neku groaned. He then tripped on his left heel, making him fall to the ground. "Crap!"

The D-Class students caught up to him and the leader grabbed his collar.

"Can't we just talk?" Neku said before… the D-Class students and him got whacked by some some sort of whip making the students get flown away while Neku was sent towards a wall. The different colored eye teen looked to see some sort of creature that resembles a chameleon.

The D-Class students ran away in panic at the sight of it while the Chameleon Imagin sees Neku about to run away.

"You're not getting away." the Chameleon Imagin said before running after him.

Neku was running but he tripped again and he sees the Chameleon Imagin and he blew fire at him, Neku rolled out of the way and was about to run again but the Chameleon Imagin whipped his back.

' _C'mon! Can my luck ever get worse!?'_ Neku thought as he crawled backwards away from the Chameleon Imagin a bit before…

 ***SLASH!***

The Chameleon Imagin was suddenly slashed on the back and was thrown aside by Momotaros.

"Man, I don't who wished for this kid to be hurt but that's pretty low even for you." Momotaros remarked.

"Who the hell are you!?" the Chameleon Imagin exclaimed.

Momotaros looked at Neku.

"Hey kid, I'm gonna have to borrow your body for a moment." Momotaros said.

"Huh?" Neku questioned.

Momotaros turned transparent and jumped into Neku, causing him to make his sapphire blue eye to turn red and his hair spiked up and has a red streak.

M-Neku got up from the ground and he got something that looks like a black pass out on one hand and a belt in the other. The belt had a red, blue, yellow, and purple next to a circle that had a T with a tip pointing to the right. He placed the belt on and pressed the red button which soon played an electric keyboard kind of tune.

"Henshin!" M-Neku announced as he swiped the Pass over the circle.

" **SWORD FORM!"  
**  
Red pixels came out of the belt before forming up on M-Neku. M-Neku was now donned in a black bodysuit with a chest plate is black and white with the white parts higher up with a silver line in the center that looks like train tracks. The helmet has a silver line running down the middle with a silver mouthplate and black eyes. This is Kamen Rider Den-O Plat Form.

Soon red pieces of additional armor then appeared on his shoulders and chest as well as black armor trimmed in yellow snapped to his back. A red metal peach slid over the helmet and snapped onto the front before splitting in two, the points extending to become antennae and the two halves of the peach now resembling eyes. This is Kamen Rider Den-O Sword Form.

 **(Kamen Rider Den-O OST: Double-Action Sword Form)**

"Ore… Sanjou!" Den-O SF announced while doing his pose.

"Den-O!" the Chameleon Imagin growled.

" _Huh? What's going on!?"_ Neku exclaimed in his mind.

"Ah! You're a Singularity Point!" Den-O SF said.

" _A what now?"_

"I see, so you just unknowingly possessed a Singularity Point?" the Chameleon Imagin said.

"Shut up!" Den-O SF said. "Look, I'll explain this after we beat this guy."

"… _Alright. Just don't hurt my body too much." Neku said._

Den-O SF smirked.

"Good. Now listen here ya tokage(lizard)-yaro, From the start to the finish, I'm at a climax!" Den-O SF declared.

The Chameleon Imagin used his whip at him, but Den-O SF deflected it and he got two metal pieces then placed them together then tossed it up in the air and grabbed two more pieces then jumped into the air combining them, which turned it into a sword. Den-O SF then went down to the ground and slashed the Chameleon Imagin, causing sparks to come off.

Den-O SF then slashed the Chameleon Imagin twice and easily dodged an incoming strike from him before he slashed the green Imagin multiple times, which made the Chameleon Imagin to roll on the ground. He used his whip to strike him, but Den-O SF slashed the incoming whip with ease and slashed the Chameleon Imagin multiple times again, making him fall on his back.

"Now it's time for my Climax!" Den-O SF announced as he got out the Rider Pass and placed it over the belt.

" **FULL CHARGE!"**

Red energy came from the belt and went towards the sword. The blade then flew out of and floated in the air.

 _"Hissatsu! Ore no hissatsu waza! Part 2 dash!"_ Den-O SF then swung the bladeless sword towards the Chameleon Imagin. The floating red blade followed its arc and put a large cut onto the Chameleon Imagin. And with that the Imagin exploded.

 **(End Song)**

" _How was that a dash?"_ Neku said.

Den-O SF ignored that comment and took of his belt, making him revert back to M-Neku. The possessed teen checked his watch before smirking and started to walk at another direction.

" _Hey, where are we going?"_ Neku asked.

"The place I crash at." M-Neku said and, as if on cue, DenLiner appeared from a rainbow colored portal and stopped near him.

" _Whoa…"_ Neku said in awe as M-Neku entered a door.

M-Neku just entered the dining cart of DenLiner before Momotaros jumped out of Neku. The different eye colored teen noticed the other three Taros along with Owner and Naomi.

"Naomi! Coffee!" Momotaros said as he sat down at a table.

"Hai~!" Naomi cheered before preparing his coffee. Neku, however, looked around DenLiner and checked outside the window only to see that the entire train is somehow in a wasteland.

"You're very curious, aren't you?" Owner said as he caught Neku's attention.

"Well yeah. I'm also surprised to see a creature that tried to attack me and another one possessed me to turn into an armored warrior. Which is something I'm also curious of." Neku said.

"It's only natural for some people to be curious." Owner said as he took a bite out of his rice.

"Yeah." Neku said before looking at Momotaros.

"What?" the red Imagin asked after noticing that look.

"I want an explanation on who you guys are but…" Neku bowed politely. "Thank you for saving my life."

"No problem kid." Momotaros waved it off and Naomi served him his coffee. The red Imagin took a sip before looking back at Neku. "You got a name?"

Neku stood straight and nodded.

"It's Neku… Neku Nogami." Neku answered.

That caused Momotaros and Urataros take a spit take from their coffees while Ryutaros messed up his coloring and Kintaros woke up to that.

"EEEEHHHH!?" the Taros yelled.

' _The heck…?'_ Neku thought.

* * *

 **(Preview)**

" **NEXT TIME ON ASSASSINATION DEN-O!"**

 **Neku:** You guys are from another world!?

 **Momotaros:** So we gotta kill that octopus?

 **Karasuma:** This classroom is currently the only place where he can be killed!

 **Neku:** This school is not only strict, but it also has a system where you can be discriminated and treated as the lowest of the low.

 **Koro-Sensei:** Allow me to give you advice as your teacher.

 **Neku:** I really hate fighting and killing, but after what I've been through; I really have a choice but to fight.

 **Momotaros:** Teme, Tako-Sensei!

" **TRAVELING THROUGH TIME, HERE I COME!"**

* * *

 **And done! Well now that I'm finally finished with the first chapter I can go to bed because that took me all night now. Anyway, be sure to leave a review or message me with questions or comments regarding the story. And don't forget to check out my other stories as well. Goodnight.**


	2. Chapter 2

**Hey guys, I'm sorry that it took so long to update. Slow progress and my life to deal with. But anyway, here's Den-o!**

 **I don't own both shows.**

* * *

 **Timeline 2: Decision Time**

"It's Neku... Neku Nogami." Neku answered.

That caused Momotaros and Urataros do a spit take from their coffees while Ryutaros messed up his coloring, and Kintaros woke up to that.

"WHAAAAT!?" the Taros yelled.

 _'The heck...?'_ Neku thought.

"Nogami!?" Momotaros exclaimed. In all honestly, he or the Taros never thought there would be another Nogami or the fact that they would meet another one! Hell, they already know three Nogamis which is Ryotaro, who was born in the timeline they fought in, his older sister Airi and his future grandson Kotaro!

"Yeah. That's my surname..." Neku was actually wondering why these guys were reacting weirdly to his surname. When he arrived at E-Class for the first time or when Koro-Sensei was taking attendance, no one reacted like these guys.

Before he could say anything else, all four Taros approached him in a comical fashion.

"Are you actually relative to Ryotaro!?" Urataros asked.

"If you are, how is he!?" Kintaros added.

"And why is the moon destroyed!?" Momotaros said.

"How is Onee-chan!?" Ryutaros asked childishly.

"H-Hang on a-" Neku tried to sort things out.

Owner got instantly tired of this shenanigan, then he loudly placed his cane down hard on the floor that made an echo. That caught everyone's attention and looked towards the DenLiner Owner.

"Enough, give the boy some space." Owner said sternly with a comical dark commanding aura.

Panicking, Momotaros went back to his table and took a sip of his coffee, Urataros did the same, Kintaros went back to his and has gone back to sleep, and Ryutaros went back to his coloring.

Neku couldn't help but notice that they were all sweating bullets.

 _'Scary...'_ he thought.

Owner simply approached the different eyed teen and gently sat him down in front of the counter.

"Naomi, give this boy a drink and whatever he likes please."

"Okay~!" the stewardess of Denliner cheered as she approached the junior high school boy. "What would you like to order?"

Neku thought about it for a few seconds, then made the obvious decision after hearing his stomach growl.

"You got any burgers and grape juice?"

"Coming right up!" she began to work on his order, starting with the drink.

The assassin-in-training waited patiently for a few seconds, then he noticed Owner staring at him intently. The DenLiner conductor patted his back before sitting on a seat behind the young teen.

"I have some questions, even on behalf of everyone here if you're willing to answer." Owner said as he began eating his fried rice.

Neku blinked in confusion. In a situation like this he should be the one asking questions, not the other way around or anything like that. But these guys look like they really need answers for a few things, and there's the feeling that they're not around from here.

But that's what it is, just feeling.

"Here's your drink!" Naomi went in front of Neku while placing his grape juice in front of him with a coaster on the bottom.

The two-colored eyed boy took a sip of it before looking at Owner.

"What do you want to know?" Neku asked.

* * *

Back where Momotaros defeated the Chameleon Imagin, some wind blew around making some sand that was hardly noticeable fly in the air while a big pile of it is on the ground.

A male figure in a hood walked towards the big pile of sand slowly before kneeling down to it, then went through his pockets and took out a colored crystal of some kind. The figure stared at it momentarily before he placed it on the sand, then buried it within said grains/remains of the Imagin

The figure stares sternly at it before sighing and shaking his head. He was about to walk away, but he just noticed the buried crystal glow in the Chameleon Imagin's remains and the sand that flew away is coming back to the pile.

The remains formed into a resurrected Chameleon Imagin before said monster noticed the hooded man.

"Go." the man commanded. The Chameleon Imagin nodded in recognition before it turned into a ball of light and flew away from the area.

The man in the hood smirked before he too left the area.

* * *

 **(DenLiner)**

Neku finished answering Owner's questions, or interrogation in this case, with an explanation about the unnatural stuff he knows prior to meeting Momotaros and encountering the Chameleon Imagin. Most of which includes how the moon was destroyed, Korosensei, and how the Japanese government is giving them a mission to kill said octopus teacher.

'Jeez, explaining all of this complicated stuff is hard...' he mentally complained.

Owner had two fingers against his chin, thinking really hard about something. From what Neku had explained, this world is in danger because of how powerful this Korosensei is. At first, he sounds like a model and then a planet destroy the next. On the other hand, this octopus sounds rather interesting and someone he would like to speak with for the sake of inspection.

"So all you gotta do is kill that octopus?" Momotaros asked, wanting to break the silence.

"It's not that simple. Korosensei is-" Neku stopped there when he notices Owner standing up from his chair.

"Well regardless of that…" Owner approached the teen with his stoic expression. "You just proved my own theory that we're in another world."

Instead of being surprised, Neku just had a deadpanned expression as if he's heard of this situation and someone saying that before.  
And he did, but that's only in fiction though. Plus, being in a some kind of supernatural desert inside a flying train is just icing on the cake along with his teacher.

"You guys are really from another world?" he asked.

"HOW ARE YOU CALM AT THAT!?" Momotaros comically exclaimed.

"To be honest, entering a flying train and ending up in a magical desert that isn't supposed to be nearby is actually pretty evident enough for me. That, and you guys could be from another world or time, according to what I've read in manga and watch on TV. There's even the fact that monster and the red guy appearing out of nowhere before I got changed into some futuristic looking armor. So after experiencing that, I'm just gonna go with the fact that you're from another world." Neku explained.

 _'This kid's very sharp!'_ Urataros thought.

"Hey! I have a name, it's Momotaros!"

 _'That explains why he looks like Momotaro from the storybook itself.'_ Neku snarked.

Owner mentally chuckled. There was also the fact Neku claimed he was surprised earlier, but he'll let that slide for now. Moreover, he is quite impressed on how sharp the boy is though.

"Well then, that gives us less time to explain things. As you said, we're from another world and we're also from another time." Owner stated.

"So not only are you people from another world, but you're from a different time period?" Neku deadpanned.

"Indeed." Owner nodded. "And the train we are currently in is called the DenLiner...! This train only arrives when a person is carrying  
a Rider Pass, the device you are currently holding, and at the same hour, minute, second, and time. For example, 05:05:05, 11:11:11, and so on. The Rider Pass that you're holding is a new one with an arrival and departure feature of its own." he explained.

Neku blinked before looking at the Rider Pass, and sees that Owner is right.

"That explains why Momotaros was looking at my watch." he remarked as he observed it. _'I wonder if this has any other features...'  
_  
"Now then..." Owner cleared his throat, catching the unlucky teen's attention. "Do you have any other questions?"

"Well I'd like to know whatever the heck that monster, and the red guy is." Neku said, already forgetting the name.

"HEY!" Momotaros exclaimed.

"If you must know…" Owner took a bite of his fried rice. "They're called Imagin."

"Imagin?" Neku questioned as he took a sip of his grape juice.

"The Imagin were originally beings of the distant future who lost their physical forms due to an event in the past erasing their own time, becoming dependent on the memories of others in order to survive." Owner started.

"Seriously? Then how do they get their physical forms?"

"A wish." the older man answered.

"A wish? So they're kind of like genies?" Neku asked. _'Also, that sounds a bit cliche.'  
_  
"Not quite, the Imagin forget their pasts but they keep their personalities as a result of having the future being destroyed. So they go to a certain year in time to find weak-willed humans and possess them, thus forging a wish while obtaining a physical form in the process through their host's imagination." Owner explained.

"Imagination?" Neku rose a brow before looking at Momotaros, then at the rest of the Taros. "So these guys, for instance, got their forms through a host that imagined them to be like that just by having… I dunno, an imagination from childhood from a storybook or something?" he guessed.

"Correct!" Owner said in a cheery tone.

 _'That doesn't fit his image at all!'_ Neku mentally exclaimed.

"Here's your burger~!" Naomi announced while placing said food in front of him.

"Oh, thanks." Neku took it before taking a small bite. "I remember that Imagin trying to attack me and those guys from another class, so I think it's safe to assume that wish is for Kunigaoka students to be injured."

"Correct. In fact, the only way for most Imagin to fulfill a wish is through hazardous ways." Owner nodded as he took a bite of his fried rice.

"Alright, so where do I come in? I recall Momotaros calling me a single-something." the assassin-in training asked.

"Singularity Point." Urataros started, taking over for Owner. "They're a certain type of human that can exist outside of time, and be immune to any effects to changes in the past. They even have the ability to suppress an Imagin's will when it comes to taking over their bodies, and avoid any temptations by an Imagin's offer for a wish. They're even suitable for the gear that Sempai used while controlling your body, it's called the Den-O Rider Gear. Well, either way, even we can use Den-O's power without a Singularity Point."

That part caught Neku's attention.

"Enough talk!" Momotaros spoke up and approached the teen. "Neku, we'll be counting on you for fighting against those guys!" he patted his shoulder. "Okay?"

"No thanks." Neku replied without a second thought.

"Alright, with this we…Wait, what!?" Momotaros exclaimed in shock.

"I don't like fighting much, and I already have a lot on my plate with Korosensei." stated Neku before looking at Owner. "Sorry for asking this, but can you drop me off at this address?" he took out his i-Phone and showed the older man the address of his home.

"Very well, lucky for you we'll be there in a moment." Owner nodded.

"Thanks."

"Hang on a moment!" Momotaros spoke up. "Why don't you like fighting!? I mean, it's fun and think of the adrenaline you get through it!"

"There are other ways for people to get adrenaline without doing the stuff they don't like. Or anything physical, really." Neku sighed, looking at the Oni Imagin. "And judging from this conversation, you're only in this little team because you enjoy fighting."

"Well you're not wrong there, and I also intend to look for stronger guys!" Momotaros puffed his chest with pride.

"Neku-kun, we're at the destination now." Owner said.

 _'Wow, that was quick.'_ Neku thought. He finished the rest of his grape juice and was about to leave with his burger in hand, but then Owner stopped him with his cane.

"Just think about it for a few days." Owner advised.

The boy looked at him for a moment. And then he spoke, "...Sure." Neku was about to pace through the exit, but then the door stopped part-way all of a sudden causing him to accidentally trip on his way out after his food collided with it. He even hit his forehead against the wall in the process.

"Ow..." Neku moaned. "Good, my burger isn't smushed."

"That kind of luck is familiar..." Momotaros noted.

"Yeah. Good times actually..." Urataros chuckled.

* * *

Neku stepped inside his apartment while taking a bite out of his burger and then sits down on the couch.

"Man, what a day..." he said in exhaustion. He actually wanted to come back here after school to study for a bit and then make dinner. But now...he's way too exhausted to do that.

The assassin-in-training suddenly felt pressure on his lap, then looked down to see a small black and white dog with black eyes.

"Hey, Iggy." Neku smiled then pets the dog's head, causing it groan in pleasure. "Not much for dinner tonight, but I still have plenty of burger meat left." he took a couple of fair pieces of it and places it next to him.

The dog, Iggy, went towards the pieces and starts eating it.

After living alone for a while, Neku started to feel a bit lonely so he found this dog and decided to keep him. He gave him the name 'Iggy', because he almost resembles the Iggy from one of his favorite series, JoJo's Bizarre Adventure Part 3: Stardust Crusaders.

 _'Maybe I should play some games after my evening walk with Iggy before going to bed.'_ he thought.

* * *

At one of the subway stations, people are either waiting for the trains of their intended destinations or getting off other trains. Some people were also hanging out with their friends or just working part-time jobs at night.

However, one of the trains is infested with a certain something.

Inside the train driver's car, the driver of said train lied on the ground with blood coming out of his mouth and stomach, while the camera was destroyed. The Chameleon Imagin stood in front of the control panels.

"Who knew I'd have a contract holder with such a devious mind?" the Chameleon Imagin laughed before placing his hand on a lever and pushing it. That caused the train to start speeding up. As the train started picking up speed, a train car start making sparks and tipping, making the passengers inside began to panic. The train then passed a platform and then start to cause destruction, making the people who were waiting to run away.

* * *

The alarm clock went off, causing a sleepy Neku to groan in annoyance and hit the button to turn it off.

"Ugh, what a weird dream." Neku murmured as he slowly got out of bed. The dream was interesting, though. It was about a train that can travel through time, which is actually kind of desert, and these monsters are spawned from within. Well, as interesting as it was, it was still nothing more but a dream.

Neku scratches the back of his head and went to take a shower. The assassin-in-training went through his closet, then grabbed his uniform and towel for when he comes to clean himself afterwards. After opening the door and walking into the hallway, he heard his TV all of a sudden...

Pacing towards the living room, he noticed Momotaros watching TV while drinking coffee, Urataros making breakfast, Kintaros snoozing on his chair, and Ryutaros drawing pictures on the floor.

"Yo, Neku!" Momotaros greeted.

"Morning." Urataros said.

"Good morning!" Ryutaros added.

Obviously, Kintaros was still asleep. So yeah, nothing...

 _'Oh, come on! It wasn't a dream! Just my luck...!'_ Neku mentally complained.

"Why don't you look happy to see us?" Urataros asked.

"For starters, you came in here without asking. And that's called breaking an entering by the way. Secondly, I don't want to be involved in whatever trouble you have in this world." he stated.

"You didn't seem to mind when we came in." Urataros pointed out.

"That's because I was sleeping!" the teen exclaimed.

"Well too bad!" Momotaros started, standing up and approaching the teen. "Since you're the only Singular Point we have, you're gonna help fight the Imagin whether you like it or not!"

"Does the word "pacifist" mean anything to you?" Neku deadpanned.

Momotaros blinked in confusion. "What's a pacifist?"

That just caused Neku to groan.

"Look, if I recall, you told me that you can already transform without my help, so that just proves you don't need me. Even if you wanted a guy unaffected by time, I'm sure there's one that's willing to fight out there." he said.

"True. There is that possibility...but we also need one for reasons other than being unaffected by time." Urataros said.

"I don't have time for this! I gotta take a shower and head to school." Neku said, heading out of the living room and started walking towards the shower.

A few minutes later, Neku came out wearing his uniform and noticed Urataros placing food he prepared on the table.

"Aren't you going to have breakfast? After all, it's the most important meal of the day." Urataros said.

"We hardly know each other and you're acting like my mom or something..." Neku said.

"Well, I was just letting you know that..."

"I'll just breakfast on the way there." Neku opens the door and then closed it as he went outside.

"You know, for someone who's supposed to be Ryotaro's counterpart, he sure is different personality wise." Urataros remarked.

"That's going to take some time getting used to." Momotaros agreed.

* * *

At least fifteen minutes away from his home, Neku yawned while he's on his usual path to the train station.

' _If they're gonna stay at this time and in my home, this will be proven to be difficult to get used to them.'_ he thought. Despite him getting lonely and having Iggy around, he's gotten used to living alone and having a peaceful time whenever he's not at school or hanging out with anyone that hasn't visit his home.

Before he could think of something else, he stopped near a TV behind a window and it was the news that caught his attention. It showed a footage of last night that was related to a train accident, causing some destruction to one of the platforms and it even injured some people in the process.

' _These are scary times we live in...'_ Neku thought.

" _You're telling me."_ Momotaros' voice was heard from out of nowhere, startling the heterochromia teen.

"W-What the-!?" Neku nearly exclaimed in a loud tone, not wanting to attract any unwanted attention. "Where are you?"

" _I'm inside your body."_

Neku blinked before noticing a trail of sand behind him before saying and remembering about yesterday's explanation. Looks like he can now talk to him via telepathy if he tries hard enough.

Neku thought hard for a moment before thinking, _'Well why are you here?'_

" _I wanna see what this octopus guy is like, and see if he'll be a worthy opponent for me to reach a climax on him!"_ he could've sworn that he felt Momotaros smirking with pride in his head.

' _Is that all...?'_ he said.

" _Of course it is, why?"_

' _Nothing...'_ Neku sighed before he continued walking.

Momotaros, after blocking out any thoughts from each other, sighed in relief.

' _I can't let him find out...'_ the red Imagin thought.

* * *

 _ **(Flashback-Three Minutes Ago)**_

" _Dammit brat! Give me my pudding!" Momotaros yelled while chasing Ryutaros around, and causing damage to the place in the process._

" _No way! I don't wanna!" the Dragon Imagin laughed._

" _Well at least we have more room than the dining cart." Urataros sighed while cleaning the dishes._

 _Kintaros was snoring peacefully, yet loudly, before he was accidentally hit with a book on the head. That caused the Bear Imagin to stop snoring and slowly open his eyes._

" _Is it time for breakfast yet?" he yawned before standing up. "Good morning! Where's Neku?"_

" _He left for school already." Urataros answered_

" _WHAT!?" Kintaros exclaimed in shock. "I didn't even give him the good morning I prepared for! I was going to give him a hug to make his sleepiness cry along with the floor!"_

" _That would disturb the neighbors downstairs." Urataros remarked before looking around. "But besides that, this place seems like an expensive place to live in and it's very nice. I wonder if he's part of a wealthy family..."_

" _Who cares about that now!?" Momotaros exclaimed._

 _Ryutaros laughed as he attempted to go over the couch, only for him to trip backwards and fall to the ground while letting go of the pudding in the process. The Dragon Imagin moaned in pain before he used his hands to get out of the position he was in, then he felt heavy breathing in front of him. Blinking in slight curiosity, he looked in front of him to see Iggy sitting down._

 _The Oni Imagin caught his pudding just in time before yelling, "HELL YEAH! Don't mess with your superior brat!" Momotaros was about to eat the pudding, but then he heard the sound of barking. That caused his spine to shiver in recognition of that bark, then looked at Ryutaros playing with a puppy._

" _Good boy!" Ryutaros giggled._

 _Urataros came into the room with an apron and cleaning supplies before noticing Iggy._

" _Oh, a dog. I wonder how Neku got that dog into this apartment." Urataros remarked._

 _Momotaros was frozen for a couple of minutes before..._

" _WAIT FOR ME NEKU!"_

 _He turned into a glowing orb of light and flew out of here while screaming like a coward._

* * *

 **(Present)**

No matter what, Momotaros cannot let Neku found out about his fear of dogs!

"So you're scared of dogs?" Neku said.

So much for that.

" _HOW DID YOU KNOW!?"_

Hearing that, Neku smirked at the Oni Imagin's reaction.

"Thanks for the information about Singularity Points yesterday." he said coolly before crossing the street. But at the moment he took a step on the pavement, a car appeared randomly and it hit hit the unlucky teen. That caused him to fly at full speed towards telephone pole and hit his head.

Neku moaned while falling down with his eyes swirling and blood leaking from his head.

" _Hey Neku! Are you alright!?"_ Momotaros exclaimed in concern.

"Y-Yeah..." the assassin-in-training assured before he slowly got up. "Don't worry. This happens a lot."

" _THEN HOW ARE YOU STILL ALIVE!?"_ the red Imagin shouted, causing the middle schooler to wince.

* * *

After getting on the train, Neku got the first aid kit he packed out and wrapped a bandage on his head, with Momotaros' help in secret that is. Now he's on the mountain where his class is at while complaining at how he was almost late to the train due to his luck.

" _Why is your classroom on this mountain?"_ Momotaros couldn't help but ask. Usually, classrooms are at normal school buildings where it's easy to go to. Not on a mountain that's a few meters high and away from a main building.

"I dunno, I never bothered to wonder why this classroom is on a place like this nor did I bother to ask about it." Neku replied.

" _You have no sense of adventure..."_

"Yeah well you have no sense of personal space when it comes to possessing, in my opinion, so we're even." he rebutted.

Before Momotaros could say anything else, Neku noticed both Nagisa and Sugino hiding behind a tree and bush. Feeling curious, he walked towards the two.

"Hey guys." the different eyed teen greeted.

Nagisa turned and noticed his friend before saying, "Hey Neku."

"Watcha doin'?"

"Come here and you'll know." Sugino whispered.

Neku crouched down before moving towards the bush, then looked to see Korosensei a few meters away sitting on a beach chair while reading a newspaper and having a drink.

" _So that's the octopus, he doesn't look like much."_ Momotaros noted.

' _Don't let your eyes fool you.'_ Neku replied.

"As you can see, it's Korosensei's daily routine to relax behind the school building every morning before homeroom, with a drink and an english newspaper he bought while stopping by at Hawaii." Sugino summarized.

" _He stopped by Hawaii?"_ Momotaros asked.

' _I'm guessing you weren't listening to a part of my explanation about the teacher yesterday on the train.'_ Neku mentally sighed before looking at Sugino. "Have you been observing him from Day 1?"

"No, you gotta thank Nagisa for that." Sugino said.

"Oh, that makes sense. He did looked like he's been paying strictly attention to him." Neku recalled.

"Yup, thanks Nagisa." Sugino grinned.

"No problem, good luck Sugino." Nagisa smiled.

"10,000,000,000 Yen here I come!" Sugino nodded before getting into a pitcher stance with a baseball covered in Anti-Sensei BBs in hand.

" _Why a baseball?"_ Momotaros asked.

Neku ignored him as he watched Sugino throw the baseball at the teacher. Just when the ball is a few millimeters away...

"Good morning!" Korosensei greeted, catching the three off guard. "Now, show me your best greeting! No mumbling, you hear?"

"G-Good morning, sir." Nagisa said.

"Morning Korosensei." Neku added.

Sugino was still surprised, evident of him looking at the spot Korosensei was at and where he's at now. So yeah, no greeting here...

" _How in the hell is he so fast!?"_ Momotaros yelled.

' _...Did I forget that he can move at Mach 20 speed and fly?'_ Neku mentally deadpanned.

" _WHAT!?"_

"Embedding those anti-me BBs into a baseball? Now that's a very fine idea. Much quieter than an airsoft gun, that's for sure." Korosensei obsevred. "However, the ball moved so slow that I've gotten bored, and touching the pellets directly would've been bad for my health. So in the end, I popped over to the equipment shed and grabbed a baseball glove."

That explanation caused both Nagisa and Sugino to have comically disbelieved expressions.

"I guess that's what to expect from a guy that moves at Mach 20 speed." Neku nervously remarked. _'I'm betting that he has a great sense of smell and sniffed the sweat on the ball...'_

"I do hope you can kill me, before graduation that is." Korosensei laughed with his green stripes appearing before walking off. "Now then, it's time for homeroom."

"Yes sir..." Sugino slumped down, causing two friends to look at him.

At that moment, Momotaros suddenly possessed Neku and his eyes flashed red for a moment.

" _Hey, what're you doing!?"_

"What does it look like?" M-Neku muttered under his breath.

M-Neku quickly, while silently, walked up to the octopus teacher and placed his hand in his pocket. Guessing that it's the Anti-Sensei knife due to the texture, he took it out while slowing down slightly. M-Neku stopped at the position he's at before throwing the knife at the back of Korosensei's head, but the knife suddenly disappeared along with his target.

"So you were gonna go for the classics." M-Neku turned to see Korosensei carrying both the ball and the knife. "I heard your footsteps and smelled you coming, especially on how your hands were sweating from holding too tight. Nurufufufufu~! But if I were you, I'd try to be more creative on how you try to attempt to kill me~!"

Hearing that, M-Neku gritted his teeth in anger while muttering. "Damn..."

Nagisa saw the entire thing. While he was not only surprised to see Neku trying to kill, but he was also surprised at the sudden change. But besides that...

Doesn't he seem different?

" _I'm really glad that my voice doesn't sound different at all after possession."_ Neku sighed.

* * *

 **(After Class)**

"Now then class, I have some business to take care of today, so if you'll excuse me..." Korosensei approached the window.

"Business?" Yuma Isogai, the male class rep with black hair, asked curiously.

"Yes. I have a game to catch in New York." Korosensei opened the window and flew out of here at Mach 20, causing dust clouds to cover up the inside of the class.

"There he goes." Yoshida said, waving some dust away with his hand.

"What's his deal?" Terasaka grumbled.

 _"About time! How do you deal with such boredom anyway!?"_ Momotaros asked.

 _'Don't ask me, it's part of a school life and I'm not Horace Mann.'_ Neku mentally replied.

"Who's that?"

 _'The guy who invented school.'_

"It'd be nice if he brought back some souvenirs for us once in awhile at least." Hinano Kurahashi, a female student with orange hair, remarked.

"But who'd want something to remember their assassination target by?" Megu Kataoka said. She's the female class rep and she has brown hair held up in a ponytail with presumably dark brown eyes.

"Well he could bring us a snack. That way, it wouldn't stick around." Kurahashi suggested.

"That's one way of looking at it I guess." Kataoka said.

"I'm pretty sure that he couldn't buy us that much snacks, I recall him trying to count up the money he actually earned." Neku said.

"That's a good point. But I wonder if he would buy booze for us." Hiroto Maehara joked. He's a fairly tall teen with wavy short orange hair and light orange eyes.

"Weren't you listening?" Neku sighed.

"He's right, and besides we're underage." Isogai said.

"Yeah, I think snacks would be for the best." Kurahashi said.

"Or maybe a blonde beauty! Hell yeah!" Taiga Okajima added with ecstasy. He has short black hair in a butch cut and thicker brows.

"Right?" Maehara grinned.

 _"These two are perverts, but not as bad as the turtle."_ Momotaros noted.

 _'...Why am I classmates with these two again?'_ the unlucky student thought.

"Karasuma-san!" Isogai spoke up.

That caught the attention of the entire class, especially Nagisa since he was the first to notice and the blue haired boy is in front of the older man.

 _"Who's he?"_ Momotaros asked.

 _'He's an official agent from Japan's Ministry of Defense.'_ Neku mentally replied.

"How's it going? Any clues on how to kill him yet?" Karasuma asked.

"...Clues?" Nagisa said.

When the older man mentioned that, the entire class was already down in the dumps and they were either looking down, leaning on their desks, or just staring off into space. No one could blame them though, thanks to their school's reputation no one can expect either one of them to succeed in trying to injure the monster or find a weak point.

"Well, we are the E-Class." Kirara Hazama remarked. She's a slender girl with wavy, shoulder-length black hair and thick eyelashes.

"It's impossible, Karasuma-san." Isogai reasoned.

"He's way too fast!" Koki Mimura added. He has orange-brown hair styled in a bowl cut and green eyes.

"No one can kill anything that flies at Mach 20!" Okajima said.

"Indeed, no army is capable of that feat." Karasuma admitted.

"Exactly!"

"But you are the only ones who have this opportunity. For whatever reason, he insists on being your teacher. Left to his own devices, coming next march, he'll blow up the Earth. One look at that carved up moon and you'll know that when that day comes there's no saving us. He's too dangerous to be left alone. This classroom is the only place he can be killed." Karasuma said.

Hearing the serious tone, Neku looked down to the floor in deep thought. But before he could think of anything, he has a sudden headache and placed his left hand on his temple. He was confused for a moment before figuring out the cause of it.

 _'Momotaros, don't!'_ he mentally growled.

 _"Aw come on! I wanna assure this guy that we'll reach a Climax on the octopus bastard's head!"_ Momotaros yelled.

 _'No, you're not!'_ he replied.

 _"Yes I am!"_

As they were bickering, Neku was struggling to hold the red Imagin back while his eyes were flashing red and back to normal. Obviously a sign that he was trying to make sure that Momotaros doesn't a possess him.

Nagisa noticed his unlucky friend's state before asking, "Hey Neku, are you alright?"

"Yeah... I'm just feeling a bit unwell, I'm sure it'll pass." he assured before excusing himself from the class.

* * *

Once he was outside and far enough away from the building, Neku slammed his head on a nearby tree which caused his eyes to stop flickering.

 _"What'd you do that for!?"_ Momotaros yelled.

"Well unlike you, I'm not the type to stand out in a crowd. Besides, if they find out about you and the others they'll have more than enough on their plate as it is." Neku replied. He's okay with talking out loud like this since there's no one around.

"Relax they won't find out about us, and what's wrong with wanting to stand out?"

"I've never been into any situations like that before meaning I don't much experience. Also, that's just something you read in fiction or watching TV, standing out can get you a lot of unwanted attention and into trouble. Have you ever been into those kinds of situations where this Ryotaro guy got into trouble?" Neku asked.

In his mind, Momotaros opened his mouth to deny what the teen said, but then he recalled a few moments and situations where Ryotaro has got into some unwanted trouble due to him and the others. The Red Imagin sighed in defeat, already accepting the idea.

"That's what I thought." Neku said.

"Whatever! I'm gonna go get some coffee!" Momotaros huffed as a silhouette of his body appeared out of Neku, then he flew up in the air before disappearing.

"Now to completely block him out..." Neku said before concentrating hard for a few minutes. Feeling like he's done, he went down the mountain stairs.

Fifteen minutes later, he reached the train station and noticed the time on a nearby clock at the shopping stand. He was pretty early, so he has plenty of time to kill at the moment.

Before he could think of something to do, Neku took a whiff of a scent that caught his attention. He looked at the counter of the stand with a sign that said "Free Samples", and very small burgers with cheese on a platter. Giving into his weakness, the heterochromia boy grabbed the small burger.

"Enjoy." the stand owner said.

"Thanks." Neku replied before he puts it in his mouth before chewing and swallowing.

A few seconds later, his vision starts getting all hazy...

Out of reflex and confusion, Neku starts wandering around while bumping into people in the process and he kept muttering sorry if he thinks he did what he thought he did. Eventually, he wanders into an alley before tripping over some trash cans and falling down some stairs.

The unlucky teen only heard footsteps before he was passed out.

* * *

Neku moaned in exhaustion while his vision was still blurry, and his head hurts. Once his vision cleared, he looked at his surroundings and noticed that he's on a train.

"What happened...?" he muttered.

Groggily, he picked himself up by using a nearby seat and a railing for support. Neku then looked around a bit more before turning around...

"Surprise!" a whip suddenly appeared and landed a hit on Neku, hard enough to make him slam head first to a window and causing some blood to appear on his face from his forehead.

"Ugh..." Neku held his head while getting away from the cracked window. He rubbed his head before noticing the Chameleon Imagin with an arrogant grin.

"Hey again kid!" the Chameleon Imagin greeted mockingly.

"You..!?" Neku gaped as he stood up. "How are you still alive when Momotaros blew you into a thousand pieces?"

"That's a trade secret!" the Chameleon Imagin laughed.

"So what do you need me to trade for that secret?" Neku asked.

"Your life!"

"That was a rhetorical question!"

"I know that!" the Chameleon Imagin barked, then shook it off. "Anyway, my contract holder, who is a few train cars behind me, actually thought of this plan to drug and place you in this reserved train. It surprisingly worked like a charm!" he laughed.

"It's reserved? Who in the world has enough power to reserve an entire-!" Neku stopped right there in realization.

"That's right~! Surprisingly, my wish was changed to killing you, now I can do this simple and then go back to the past just like that!" the Chameleon Imagin charged at Neku before punching the teen, making him fly away a couple of meters.

"Ugh!" Neku grunts as his head was slammed against the door.

"What's wrong? Aren't you gonna summon that armor of yours again?" the Chameleon Imagin asked mockingly.

Neku gets up while wiping the blood off his face.

 _'Need to get out of here. Wish I had something to actually defend myself instead of just a BB gun and fake knife.'_ Neku thought. He didn't wanted to fight in the first place, but it could've been great for distracting the guy.

The Chameleon Imagin swung his whip, making it wrap around the middle school boy's neck and causing him to make choking sounds.

"Well if you're not going to fight, might as well kill you now." the Chameleon Imagin took a breath in to burn Neku alive.

'No choice then!' Neku pulled the whip towards him, causing his attempted killer to be pulled in due to both gravity and his weight. The different eye teen timed the right moment and kicked the Chameleon Imagin's face, with his left heel hitting the right eye. The Chameleon Imagin was then knocked away from the teen's kick, giving him the time to unwrap the whip and throw it away.

"Damn brat! That actually hurts!" the Chameleon Imagin yelled.

 _'Wow, really? I guess that unintentional assassin training helped me out.'_ Neku thought, then blinked in realization. _'Hang on, I was even taught the art of stealth and killing for these past few weeks. Maybe I can use the surroundings of the train to my advantage to get the upper hand. Then, after he's been at least ambushed or distracted, I can at least try and get away while either Momotaros or one those guys to beat him.'_

Neku closed his eyes momentarily while he formulates a plan. He hopes that it better worked out, because he's got the world's worst luck.

At this point, the Chameleon Imagin groaned while getting up, then looks at the assassin-in-training before yelling, "That's it! I was gonna give you a painless death, but now I'll kill you nice and painful!"

Neku opens his eyes then grabs the whip before looking back at him.

"I don't think you wanna fire at me full on, you said your contract holder's a few train cars from behind you. And from behind me three cars ahead, the guy driving this thing is still standing and busy. So what would happen if you killed me, and that person at the same time?" Neku taunted, hopping his idea doesn't backfire on him.

Thinking of it quickly, the Chameleon Imagin stopped after learning what Neku's trying to say. If he killed him and the conductor driving the train, then there would be catastrophic damage and it would kill his contract holder!

 _'Good, he fell for it!'_ Neku then runs away while closing the door behind him.

"Get back here!" the Chameleon Imagin roared while giving chase.

After stopping at the second train cart ahead while running at full speed, Neku noticed that the train is also moving. But that was the least of his problems right now, he needs to survive this predicament and run away afterwards! Heck, for once he was lucky that the Imagin actually took a hint and decided to stop the attack. After all, he figured that most Imagin aren't so smart after the time he spent with Momotaros today.

Shrugging those thoughts off, Neku noticed that it's dark and then looked around the for a place to hid before setting his sights on one thing.

Thirty seconds later...

The Chameleon Imagin busted through the door, then looked around to see that Neku wasn't here. How could that happen? This train is like any other normal train carts here, minus the train driver's car, but the kid actually disappeared. That just seemed impossible!

Before he could light the place up, the Chameleon Imagin felt a slam to the back of his head, causing him to stumble then look back to see Neku holding a fire extinguisher.

"Where'd you come from!?" the Chameleon Imagin demanded.

"I don't know if you know this or not, but I had a good teacher in the art of assassination these past couple of weeks. So hiding in a normal train cart in the dark was pretty easy... If you put some thought into it that is." Neku said.

"Are you serious?" the Chameleon Imagin asked.

"Yes."

"Well then stop hiding and fight me head on like a man already!" the Imagin growled while charging at him.

"Here, catch!" Neku tossed the fire extinguisher at the Imagin.

The Chameleon Imagin stumbled a bit before catching it and saying, "Ha! Even I know that's not a plan, that's just acting by instinct!" he then placed the extinguisher next to him.

Neku, unfazed, simply went towards a door before grabbing a rail handle he broke earlier before using it to force the door open, revealing the sight of buildings being passed by the train.

"You might wanna check that fire extinguisher real quick." Neku advised.

The Chameleon Imagin blinked in confusion before looking down then picked it up and did what he said. At a closer look, the Chameleon Imagin noticed one thing, it was his whip with the grip clogged in the hose of it and said whip is also tied into a knot on the extinguisher's trigger.

"Why's the whip like that...?" the Imagin asked.

Instead of answering, Neku ran at his attempted killer and attached himself onto him.

At that moment, the fire extinguisher exploded and, thanks to the wind pressure coming from outside, it helped out in throwing both opponents out of the train and falling towards the ground.

"You're crazy!" the Chameleon Imagin exclaimed.

"Well you can't blame me, I had to get you off the train or else you would've killed me either way!" Neku exclaimed.

"Damn straight!" the Imagin yelled.

"And here's this!" Neku yelled as he kicked the Chameleon Imagin with both of his legs, thus pushing the latter down to the ground and the former gaining a few meters of height.

"You asked for it!" the Chameleon Imagin turned while holding in his breath, he then aimed at Neku before the time creature blew a fireball.

"Holy-!" Neku didn't finish as the fireball engulfed him.

"Great! Now I can have the wish granted after the trouble I've been through!" the Chameleon Imagin laughed.

 **"SWORD FORM!"**

"Ore... Sanjou!" Den-O SF appeared from the flames with the DenGasher in blade mode. The Train Rider got into a diving position, which caught up on some speed in the free-fall before he slashed the Chameleon Imagin, making some sparks appear. Den-O SF landed safely on the ground, making some cracks in the process while the Chameleon Imagin crash landed into a pile of junk.

 _"Okay, I admit that was awesome. But how'd you get here?"_ Neku asked.

"I followed your scent and saw you fight off the guy before fully possessing you." Den-O SF grinned. "Hell, for a pacifist, whatever that is, you got some ba-"

 _"Spirit."_

"...Spirit, to actually take the fight to the guy." Den-O SF said.

"Thanks." Neku nodded in his mindscape, which he took note that his mental surroundings are red. "You know, I've done some thinking and I'll be honest. I really hate fighting and killing, but after what I've been through; I have no choice but to fight."

"Wait, so does that mean...?" Den-O SF's eyes widened.

 _"...Yes. I decide that I'll help."_

Despite noticing the reluctance in Neku's voice, Den-O SF grinned like a madman and started jumping before shouting, "ALRIGHT! Welcome to the team Neku!"

The Chameleon Imagin got himself out of the pile of junk before glaring at the Time Rider.

"You!" Den-O SF turned back to his growling opponent. "You're gonna pay for-"

 _"Let's just finish this guy so we can go home, I need some rest after what I've been through."_ Neku said, obviously not wanting to listen to the Imagin's rant any longer.

"Are you even listening!?"

"Okay! Now from start to finish, we're at the Climax! Let's go, let's go, let's go!" Den-O SF charged at the Imagin.

Before the Chameleon Imagin could even attack, Den-O SF slashed him multiple times before he grabbed the time monster by the head and kneed his face a couple of times then kicked his chest. The Chameleon Imagin growled before getting up and using his invisibility ability to hide, causing Den-O SF to stop for a moment as he suddenly felt a burning pain on his back. Den-O SF growled before using the DenGasher to slash the ground to make sparks appear, he noticed a slight shadow and then the Time Warrior swung his sword in that direction, making the Chameleon Imagin appear via damage and cancelling out the invisibility.

"Alright, time for the finisher! This one will also be special service!" Den-O SF announced.

 _"Special service?"_

Den-O SF didn't say anything as he stabbed the DenGasher into the ground, and placed the Rider Pass over the belt.

 **"FULL CHARGE!"**

"This our new finishing move...!" Den-O SF started as his hands and forearms glowed red. "...JoJo Version!"

 _"JoJo Version!?"_

Den-O SF charged at the Chameleon Imagin and then landed a punch to the face. Then another one, and another one, which eventually turned into a flurry of punches at high speed!

"ORAORAORAORAORA~!" Den-O SF yelled before reeling in his right fist and throwing one last punch. "ORA!"

The Chameleon Imagin felt the punch land on his face before flying towards another pile of junk. Den-O SF smirked as he walked away while grabbing his weapon, then the Chameleon Imagin exploded in the process.

"Piece of cake!" Den-O SF reverted back to Neku, only with his possessed appearance.

 _"Did you just do Star Platinum's signature attack!?"_

"Consider that a welcoming gift from me to you!" M-Neku grinned.

 _"Great...! Now let's go home, I'm tired from all of the excitement."_ Neku yawned.

"Yes sir!" M-Neku saluted jokingly.

 _"Wait, hang on."_

"What's wrong?"

 _"I think I saw something, can I have the driver's seat so I can observe what it is?"_ Neku asked.

"Fine." M-Neku let his host want back in control, then the middle schooler went towards the Chameleon Imagin's remains. He observed the sand for a few seconds before he noticed and picked up a crystal.

 _"This is interesting..."_

* * *

 **(Neku's Appartment)**

"...and that's what happened!" Momotaros finished. After he and Neku got home, the Red Imagin decided to tell the others what happened while the unlucky teen went to take a shower and crash on his bed. After having dinner, and Neku telling about his little fight from his point of view.

"So Neku finally decided to join us, huh?" Urataros smiled in amusement. "It's actually amazing that after a second fight, he suddenly decided to join us."

"Yay~! A new friend that's not a moron like Momotaros!" Ryutaros added.

"Hell yeah!" Momotaros grinned, but then realized what he heard. "Wait, what the hell did you call me!?

"An idiot!" the Dragon Imagin laughed.

"Why you-!"

"However." Kintaros spoke up, wanting to avoid a fight. "I wonder who the contract holder is... after all, we usually defeat the enemy we're battling against and destroy them after going back in time."

"Now that you mention it, Neku also mentioned that the Imagin's wish was changed to just plain out killing him. That also makes me wonder on who would want him dead. We also need to find out what that small crystal is as well." Urataros pondered.

"We'll find him eventually, a!" Momotaros exclaimed, putting one foot on the table and making a thumbs up. "And once we do, we-"

He was interrupted by a sudden arrival bark from Iggy.

"Oh, Iggy!" Ryutaros said before he starts playing with the dog.

Momotaros looked back at the adorable dog while sweating bullets.

Inside Neku's room, said boy was trying to sleep before he suddenly heard a cowardly scream from Momotaros and some rough housing. The different eye teen removed the covers from his face which revealed a tired look in his eyes.

"...Will I be okay with these guys?" Neku rubbed his temples.

In his desk drawer, the crystal shined momentarily before it faded.

* * *

 **Finally, done! So anyway...**

 ***BOOM!***

 **What the-!?**

 **"Surprise!"**

 **H-Hang on, aren't you Ichika/Faiz!?**

 **"Uh... Yeah. Ain't it obvious to you, Author-man? After all you're the one who gave creation to me and stuff."**

 **Well yeah, but how are you here!?**

 **"Hello~! It's called Fourth Wall Breaking, so you might wanna Google it!"**

 **I know what that means! What I'm trying to say is how in the world are you HERE of all places?**

 **"Oh, I just invaded the Velvet Room and the Palace inside your subconscious and did a little bit of this and that just to come here."**

 **This and that...?**

 **"Never mind that! I just have a few things to say!"**

 **What's that?**

 **"My author hopes that you enjoyed the story, and I must apologize for him for being such a lazy man that takes too long. In brain power, motivation, and other stuff that's needed for an author whether it's Novels, Manga, Light Novels, and Fanfiction. Hell, even Anime needs that kind of stuff. In fact, I'm also sorry for him being such a lazy j*** who keeps forgetting to do them."**

 **HEY! I'm neither of those things! It's just that I have my own life to do as well that even most people get exhausted of, and I'm finally free to do some more on this now!**

 **"Yeah, if you say so."**

 **I AM!**

 **"Well I'm sorry for him having the fake symptom called Writer's Block."**

 **I'll have you know, it's a real thing that even my mother agrees!**

 **"If you say so. Welp, good day and good night everybody."**

 **Oh we're not done tal-**

 **[Screen suddenly turns off]**


End file.
